1. Field of the Invention
The present invention relates to a paper-feeding system, and more particularly, to a paper-feeding system capable of switching paper-feeding statuses manually or automatically.
2. Description of the Prior Art
Please refer to FIG. 1. FIG. 1 is a diagram of a paper-feeding system 10 in the prior art. The paper-feeding system 10 includes a paper tray 12 for positioning a print medium 14, such as paper or a transparency, a burster 16 installed below the paper tray 12, a pickup arm 18, and a pickup roller 20. One end of the pickup arm 18 is connected to the pickup roller 20, and the other end of the pickup arm 18 is applied a force by an elastic component (not shown in FIG. 1) so that the pickup roller 20 is capable of applying a normal force to the print medium 14. The pickup arm 18 keeps pressing the print medium 14 so that the pickup roller 20 can press an upper surface of the print medium 14 steady.
Please refer to FIG. 2 and FIG. 3. FIG. 2 is a lateral view of the paper-feeding system 10 when print media are loaded fully in the prior art. FIG. 3 is a lateral view of the paper-feeding system 10 when no print medium is loaded in the prior art. The pickup roller 20 continues pressing the upper surface of the print medium 14 so as to apply the normal force to the print medium 14 for generating a corresponding friction force to drive the print medium 14 to move downward. The burster 16 blocks a bottom of the print medium 14 so that the print medium 14 buckles. The upper print medium 14 can be separated from other print media alone.
Because the pickup roller 20 needs to continue pressing the upper surface of the print medium so as to provide a normal force to the print medium 14, the normal force has to be overcome when positioning the print medium 14 inside the paper-feeding system 10 at a correct location. When the print medium 14 is loaded improperly, the print medium 14 might enter to a print area incorrectly. In addition, the normal force increases difficulty of repairing a paper jam of the paper-feeding system 10.